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61.
62.
In [1], we defined c(G), q(G) and p(G). In this paper we will show that if G is a p-group, where p is an odd prime and |G| ≤ p
4, then c(G) = q(G) = p(G). However, the question of whether or not there is a p-group G with strict inequality c(G) = q(G) < p(G) is still open. 相似文献
63.
Hassan Saadat S. N. Mousavi M. Saadat N. Saadat A. M. Saadat 《International Journal of Theoretical Physics》2010,49(10):2506-2511
This paper visualizes effect of dark matter on solar system and especially perihelion precession of Earth planet. The relation
between the rate of perihelion shift of Earth planet and dark matter are obtained. 相似文献
64.
A new sensitive colour reaction for nitrite determination is presented. In acidic medium, nitrite was reacted with safranine to form a diazonium salt which caused the reddish-orange dye colour of the solution to change to blue. The carrier stream, into which the sample solution was injected, was doubly distilled water. The reagent solution stream, which contained safranine dye, hydrochloric acid and potassium chloride, was mixed with the carrier in a 3-m length of silicon tubing (bore 0.5 mm) maintained at 30°C in a thermostatic bath. The absorbance intensity was measured at 520 nm. The detection limit was 20 ng ml−1 and the RSD% of 20 injections of 1 μg ml−1 of nitrite was 0.65%. Analysis can be done at a rate of up to 30 h−1. Under the optimum conditions in the concentration range of 30–4000 ng ml−1 of nitrite ion, a linear calibration graph was obtained (r=0.9999). The method was applied successfully to the determination of nitrite in sausages. 相似文献
65.
A sensitive and selective preconcentration method for the determination of trace amounts of iron by atomic absorption spectrometry has been developed. Iron forms a complex with methylthymol blue at pH=3. This complex is retained by naphthalene tetraoctylammonium bromide adsorbent in a column with a height of about 2 cm. The adsorbed metal complex is then eluted from the column with nitric acid and its iron content is determined by flame atomic absorption spectrometry (FAAS). The effect of different variables such as pH, reagent concentration, flow rate and interfering ions on the recovery of the analyte was investigated. The calibration graph was linear in the range 25-350 ng ml−1 of iron in the initial solution with r=0.9994. The limit of detection based on 3Sb criterion was 12 ng ml−1 and the relative standard deviation for eight replicate measurements of 150 and 300 ng ml−1 of iron was 3.1 and 1.8%, respectively. This procedure was successfully applied to the determination of iron in tap and sewage water samples. 相似文献
66.
Synthesis,Spectroscopy, X‐ray Crystallography,and DFT Computations of Nanosized Phosphazenes
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Zahra Shariatinia Elnaz Jalali Moghadam Narges Maghsoudi Hourieh Sadat Mirhosseini Mousavi Michal Dusek Vaclav Eigner 《无机化学与普通化学杂志》2015,641(5):967-978
Nanoparticles of nine phosphazenes with general formula 4‐CH3C6H4S(O)2N=PX3 [X = Cl ( A ), NC4H8 ( 1 ), NC6H12 ( 2 ), NC4H8N–C(O)OC2H5 ( 3 ), NC4H8N–C(O)OC6H5 ( 4 ), NC4H8O ( 5 ), NHCH2–C4H7O ( 6 ), N(CH3)(C6H11) ( 7 ), NHCH2–C6H5 ( 8 ), and 2‐NH‐NC5H4 ( 9 )] were synthesized using ultrasonic method and characterized by 1H, 13C, 31P NMR, FT‐IR, fluorescence, as well as UV/Vis spectroscopy and additionally with XRD, FE‐SEM, N2 sorption, and elemental analysis. The 31P NMR spectra of compounds 1 – 9 reveal the most up field shift δ(31P) for 9 at –11.45 ppm reflecting the most electron donation of 2‐aminopyridinyl rings through resonance to the phosphorus atom. The 1H, 13C NMR spectra of 7 exhibit two sets of signals for the hydrogen and carbon atoms of its two isomers present in the solution state in 1:4 ratio. The FE‐SEM micrographs illustrate that the nanoparticles of compounds 1 – 9 have spherical morphology and a size of 27–42 nm. From the XRD patterns, the crystal sizes were estimated to about 24–86 nm. The highest bandgap was measured for 3 (3.81 eV) whereas the smallest was measured for 8 (3.50 eV). The structures of two polymorphs of compound 5 ( 5 , 5′ ) were determined by X‐ray crystallography at 120 K. Both of these polymorphs are triclinic with P1 space group but 5 has a doubled unit cell volume and two symmetrically independent molecules ( 5a and 5b ). In structures 5a and 5′ , the phosphorus and all endocyclic atoms of two morpholinyl rings display disorder, whereas the molecule 5b does not show disorder. The strong intermolecular O–H ··· O hydrogen bonds plus weak intermolecular C–H ··· O and C–H ··· N interactions create three‐dimensional polymers in the crystalline networks of 5 and 5′ . The DFT computations illustrate that molecule 5b is more stable than 5a by –1.1062 and –0.9779 kcal · mol–1 at B3LYP and B3PW91 levels, respectively. The NBO calculations presented sp3d hybridization for phosphorus and sulfur atoms and sp2, sp3 hybrids for the nitrogen and oxygen atoms. 相似文献
67.
H. R. Aghabozorg R. Mousavi S. Asckari H. Aghabozorg 《Journal of nanoparticle research》2007,9(3):497-500
Vanadium oxide nanotubes were synthesized via two methods: (1) Adding a template to vanadium oxide gels, (2) Grinding mixture
of a template and vanadium oxide by using a ball mill. Influence of preparation method on structure of vanadium oxide nanotubes
has been investigated. Vanadium oxide nanotubes has been characterized by X-ray diffraction (XRD), Scanning electron microscopy
(SEM), and Transmission electron microscopy (TEM) techniques. 相似文献
68.
A. R. Teymourtash Javad Abolfazli Esfahani S. A. Mousavi Shaegh 《Heat and Mass Transfer》2009,45(9):1185-1198
The entropy generation due to irreversible heat transfer between vapor and liquid phases in a nucleating steam flow in a Laval
nozzle is studied. To calculate the entropy generation due to self-condensation in transonic steam flow, a thermodynamic model
is presented. The calculations of nucleating steam flow and the predictions of entropy generation rely on one-dimensional
two-phase model. This model shows that the most of the thermodynamic losses take place during the nucleation phenomena. The
effect of rate of expansion on the exergy losses is considered by decreasing the divergent angle of nozzle. Also micro-sized
pure water droplets is injected theoretically to supercooled steam right after the nozzle throat at the onset of divergent
section and the effects of injected droplets on thermodynamic losses and nucleation phenomena are investigated. The results
indicate that decreasing the divergent angle and also injection of droplets diminishes the pressure rise in transonic steam
flow and decreases the thermal entropy generation due to nucleation. 相似文献
69.
Hengameh Bahrami Mousavi Mehdi Maghsoudi Shahab 《Russian Journal of Electrochemistry》2021,57(2):149-158
Russian Journal of Electrochemistry - Sarcosine has been identified as a key metabolite marker for monitoring and early diagnosis of metastatic prostate cancer (PCa), and it is detectable in the... 相似文献
70.
Mohammad Ehsan Taghavizadeh Yazdi Simin Nazarnezhad Seyed Hadi Mousavi Mohammad Sadegh Amiri Majid Darroudi Francesco Baino Saeid Kargozar 《Molecules (Basel, Switzerland)》2021,26(6)
The use of naturally occurring materials in biomedicine has been increasingly attracting the researchers’ interest and, in this regard, gum tragacanth (GT) is recently showing great promise as a therapeutic substance in tissue engineering and regenerative medicine. As a polysaccharide, GT can be easily extracted from the stems and branches of various species of Astragalus. This anionic polymer is known to be a biodegradable, non-allergenic, non-toxic, and non-carcinogenic material. The stability against microbial, heat and acid degradation has made GT an attractive material not only in industrial settings (e.g., food packaging) but also in biomedical approaches (e.g., drug delivery). Over time, GT has been shown to be a useful reagent in the formation and stabilization of metal nanoparticles in the context of green chemistry. With the advent of tissue engineering, GT has also been utilized for the fabrication of three-dimensional (3D) scaffolds applied for both hard and soft tissue healing strategies. However, more research is needed for defining GT applicability in the future of biomedical engineering. On this object, the present review aims to provide a state-of-the-art overview of GT in biomedicine and tries to open new horizons in the field based on its inherent characteristics. 相似文献